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TitleNew geological compilation of the Liard - La Biche region provides new insights into Cordilleran structural evolution
AuthorLane, L; Fallas, K; Currie, L
SourceCSPG - CSEG - CWLS Joint Convention, abstracts; 2006 p. 140
Alt SeriesEarth Sciences Sector, Contribution Series 2005665
PublisherCanadian Society of petroleum Geologists
MeetingCSPG - CSEG - CWLS Joint Convention; Calgary; CA; May 15-18, 2006
Mediaon-line; digital
File formatpdf
ProvinceBritish Columbia
Subjectsstratigraphy; structural geology; bedrock geology; depositional history; structural interpretations; structural features; deformation; igneous rocks; intrusive rocks; syenites; volcanic rocks; Liard Basin; Pool Creek Syenite; Ting Suite; Paleozoic
LinksOnline - En ligne
AbstractRecent detailed mapping in the western Liard Basin has significantly revised previous mapping and generated new insights into the depositional history and structural evolution of this region. The area lies within a transition zone where the deformation front and Paleozoic facies and thickness trends deflect eastward. The distribution of stratigraphic units and their facies variations is clarified and facies boundaries of lower Paleozoic units are better resolved. Also, lower Paleozoic strata have been subdivided according to their equivalents on the MacDonald Platform to the south, and the Mackenzie Platform to the north. Sinuous structural trend s resolve, in detail, into an interference pattern between north- to northeast-trending structures of the Mackenzie Mountains, and northwest-trending structures of the Rockies. Intrusive rocks previously mapped as Pool Creek syenites comprise a Late Proterozoic body (Pool Creek Syenite) and an early Eocene syenite of the Ti ng Suite. Also, subvolcanic trachyte plugs of the Eocene Beaver River Alkali ne complex are associated with volcanic and volcano-sedimentary rocks. A newly documented Paleocene basalt overlies Tertiary gravels in the Beaver River valley. These new data help constrain the Late Cretaceous to Tertiary structural evolution in this part of the Cordillera. A new regional cross-section illustrates low strains, reflected by a thin Cretaceous clastic apron and low thermal maturities at the surface. Such low taper orogens reflect a dominance of low- strength lithologies. A balance of both foreland- and hinterland -directed structures above the Besa River indicates that this unit has very low strength, consistent with the low-taper geometry.